Missing the Buz -or- My Fuel Distributor is too quite andmy car runs

[Orin Eman]

Sometimes they will stop buzzing if the duty cycle gets driven down
to 5% or so... an error condition in itself and usually due to
someone playing with the mixture screw.

Orin.

> Not true - the frequency valve (duty cycle) will go to preset settings in the open
> loop mode (low temp, O2 sensor open/shorted, WOT switch actuated)  - but it is
> operated from the ECU/fuel pump relay and is always on when the car is running.
>
> Ameer Antar wrote:
>
> > Turbo motors use a frequency valve which buzzes along to regulate the
> > mixture. It sits sorta near the fuel filter. If the system is in open-loop
> > mode, it shouldn't buzz. Maybe the system can't get into closed-loop mode.
> > A bad o2 sensor, or any other sensor might cause this. I'd test the
> > resistance of the valve itself to make sure there's no short or break in
> > the windings too. Is the duty cycle showing up on the freq. valve's signal
> > wires? If the signal is there, the valve might not be responding any more.
> > Of course, you should check for vac leaks and clean or replace any aging
> > parts for the entire system. Good luck.
> >
> > -ameer
> >
> > At 12:12 PM 8/14/2002, you wrote:
> >
> > >Subject: Missing the Buz -or- My Fuel Distributor is too quite and my car
> > >runs like
> > >  crap
> > >To: quattro at audifans.com
> > >From: robert_a_dupree at bankone.com
> > >Date: Wed, 14 Aug 2002 10:18:24 -0500
> > >
> > >This I am sure is related the other message dealing with the missing
> > >Engine-Speed-Sensor code that it being observed but...
> > >
> > >I need someone to refresh my memory on how the duty cycle function works on
> > >CIS.  Or rather what are the critical inputs to re-enable the duty cycle
> > >function.  The buzz is gone, and even when using the basic quick check of
> > >moving the fuel flap up or down (while running) I don't get the buzz.
> > >
> > >As soon as I find the fuel pressure tester I will check control and system,
> > >but what other sensors, components, or functions are required for fuel duty
> > >cycle?
> > >
> > >Rob D.
> > >
> > >
> > >
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